Shuttle boxing detector for fly-shuttle looms

ABSTRACT

A relatively fail-safe fly-shuttle boxing detector for flyshuttle weaving looms is disclosed. The apparatus provides automatic shut down of a loom if a fly-shuttle fails to box or if sensing switches fail either in the open or closed mode and utilizes the normally available warp stop voltage as a source of power. The electronic circuitry disclosed provides a voltage to a motor controller which enables the loom drive motor to continue to operate only if the fly-shuttle is boxed at a prescribed time in the loom cycle.

United States Patent 1191 Amato et a1.

1 1 Feb. 6,1973

1541 SHUTTLE BOXING DETECTOR FOR 3,613,742 10 1971 Ainsworth ..l39/336 FLY SHUTTLE LOOMS 3,625,243 11/1971 Hansen et 61.1.. ..l39/336 V 2,600,667 6/1952 Mason ..l39/341 [75] Inventors: Jack C. Amato, Mme Hill; Eugene A. 2,625,183 1/1953 Dufourd et a1. ..139/341 Sansone, Belle Meade, both of NJ.

FOREIGN PATENTS OR APPLICATIONS [73] Assignee: The Singer Company, New York,

N.Y' 401,859 5/1966 swltzerland ..139/341 [22] Filed: June 18, 1971 Primary Examiner-lames Kee Chi ato, 1 pp No: lgslgg A Attorney Marshall .1. Breen et a1,

[57] ABSTRACT [31 {18.31. ..l39/336, 139/1, 139/341 A relatively fail safe fly shume homing deector for L Kilt. Shuttle weaving looms is disclosecL The apparatus p [58] Fleld of m 137/3366 l E vides automatic shut clown of a loom if a fly-shuttle fails to box or if sensing switches fail either in the [56] References C'ted open or closed mode and utilizes the normally availa- UNXTED STATES PATENTS ble stop voltage as a source of power. The electronlc clrcultry dlsclosed prov1des a voltage to a motor 3,570,550 3/1971 Budzyna ..139/336 controller which enables the loom drive motor to con- 3,373,773 3/1968 Balentine,.lr. et a1 ..139/1 tinue to operate only if the fly-shuttle is boxed at a 3.565.126 2/1971 Schlappi 139/341 r scribed time in the 100m cycle.

4 Claims, 6 Drawing Figures SHUTTLE BOXING DETECTOR FOR FLY- SII'UTTLE LOOMS BACKGROUND OF THE INVENTION The present invention relates to fly-shuttle weaving looms, and more particularly to a fail-safe apparatus for detecting the presence of a fly-shuttle in a shuttle box at a prescribed portion of the loom cycle.

A majority of present-day looms used in the weaving industry depend on an electric motor as their source of power. This electric motor is usually accompanied by a motor controller unit which functions to start and stop the motor. The motor controller unit frequently operates at low voltages and provides an ideal place for coupling protection or shut-down devices. During the operation of a loom it occassionally becomes necessary to stop or shut-down the loom to prevent damage to the fly-shuttle as well as to the warp yarns if the fly-shuttle has not been boxed at the proper time-in the loom cycle.

Frequently, prior art detection devices were mechanical devices and by means of levers and fingers they provided an abrupt shut-down by adding a stopping force while the motor was still moving or they mechanically disengaged the drive motor if the shuttle was not boxed on time. With the added weight and speed of present-day looms mechanical sensors and linkages do not perform satisfactorily. Electrical switches used in the prior art in conjunction with relay logic, although an improvement over the mechanical devices, were not fail safe. Failure of the sensing switch, which in most cases is the weakest link in such a system, in either the open or closed mode does not guarantee loom turn-off.

SUMMARY OF THE INVENTION A preferred embodiment of the present invention requires minor modification of a conventional fly-shuttle weaving loom, works in conjunction with conventional motor controller units, and provides a shut-down disabling signal voltageto the motor controller if the sensing switches fail in the open or shorted mode.

In a fly-shuttle weaving loom having an electric motor drive means responsive to a motor controller, a lay bar with shuttle boxes at both ends, a shuttle boxing detector, utilizing the principles of the present invention, comprises, first and second switch means fixedly disposed respectively on the shuttle boxes for providing an enabling voltage upon the boxing of the fly-shuttle, first means coupled between the first and second switch means and the motor controller for providing a first voltage to the motor controller, second means coupled to the first and second switch means and the first means for removing thefirst voltage a predetermined time interval after the fly-shuttle has been boxed in either of the shuttle boxes, and third means coupled to the motor controller for providing the first voltage and a second voltage responsive to the position of the lay bar in the loom cycle, the second voltage being provided only during a portion of the time the fly-shuttle is normally boxed, whereby the motor is stopped unless the motor controller is provided with the first voltage.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial plan view ofa lay bar showing a left hand shuttle box with a fly-shuttle therein, utilizing the principles of the present invention;

FIG. 2 is a view in side elevation of the shuttle box of FIG. 1;

FIG. 3 is a schematic circuit diagram of a preferred embodiment ofa shuttle boxing detector; and

FIGS. 4A, 4B and 4C are voltage timing diagrams showing the voltages appearing at various points in the schematic of FIG. 3 at various times in the loom cycle.

DESCRIPTION OF THE PREFERRED EMBODIMENT As the general construction and operation of a flyshuttle weaving loom is well known and familiar to those engaged in the weaving art, and as the invention is entirely concerned with providing a signal voltage to a conventional motor controller for stoppingthe loom in the event that a fly-shuttle is not boxed at a proper time in the loom cycle, it is only considered necessary here to illustrate and describe those parts of a loom directly concerned with a preferred embodiment of the present invention. The loom includes among other conventional parts, a shipper handle, motor controller, motor, cam shaft and cam, frame, reed, etc., all of which have not been shown for clarity.

Referring now to the Figures, and more particularly to FIGS. 1 and 2, wherein is shown a partial plan view and side elevation respectively of a lay bar 10 including a conventional shuttle box 12, fixedly mounted on the left side of the lay bar 10 and containing therein flyshuttle 14 with bobbin 16 removably retained therein.

At the left end of the lay bar 10 picker 18 is fixedly attached adjacent the upper end of picker stick 20. The picker stick 20 is mechanically linked, in a conventional manner, to the motor source by gears and levers, not shown, and causes the shuttle 14 to be picked (hit), thereby causing the shuttle to fly to the right side of the loom wherein the shuttle comes to rest in a shuttle box not shown, similar to the left hand shuttle box 12, shown in FIG. 1. The shuttle is picked from one box to the other in the usual manner during the loom cycle.

The shuttle box 12, is conventionally formed with a fixed or stationary binder arm 22 which is mounted by means of screws 24 and 26 to the lay bar 10. Fixedly mounted to the inner wall 28 of a binder arm 22 is a strip of leather 30, or other suitable material, to apply friction and clamping to the shuttle 14 as it enters the shuttle box.

A movable binder arm 32 is pivotally mounted to the lay bar 10 by means of pivot screw 34 and guide screw 36. Movable binder arm 32 has included thereon a flange 38 into which is cut slot 40. Fixedly mounted to the inner wall 42 of movable binder arm 32 is a strip of leather 44 which functions in a manner similar to leather strip 30. Binder arms 22 and 32 form the walls of shuttle box 12 in conjunction with railing 46 which is normally part of the lay bar 10. Mounted on movable binder arm 32 is a mica strip 48 for providing a long wearing surface. The mica strip 48 cooperates with spring 50 which urges movable binder arm 32 against a railing 46. Guide screw 36 cooperating with slot 40 and pivot screw 34 allows free motion. in a plane parallel to lay bar 10. All of the above described components are normally found in a conventional shuttle box.

The preferred embodiment of the present invention requires minor modification of the conventional shuttle box and consists of drilling a hole 52 and adding metal contact 54 to the movable binder arm 32. Metal contact 54 is mounted to and retained by binder arm 32 by means of a nut 56. Nut 56 also retains metal plate 58 to the binder arm 32.

Should the binder arm 32 be made of an electrically conductive material it would be necessary to mount contact 54 to the binder arm with the proper insulating materials in a conventional manner. Alternately, contact 54 can be provided by utilizing an electrically conductive binder arm 32, which is insulated (electrically isolated) from the metal lay bar 10, thereby allowing the complete binder arm itself to effectively become the contact 54.

It is to be noted that certain older looms although not having electrically conductive (metal) lay bars are frequently clad with a metal skin for strength and would normally contain rail 46 thereon. Rail 46 may be added to a wooden lay bar in the form of a metallic bracket. As will be explained later, rail 46 functions as the mating contact of an enabling switch. Other conventional types of sensors may also be utilized to sense the arrival of the shuttle 14 to the shuttle box 12 without departing from the spirit of the present invention.

Metal plate 58 has connected thereto wire 60, which is run to connector 64. The wire 60 is run beneath mica strip 48 for convenience, and is held in position against the binder arm 32 by a clamp 62. The connector 64 is retained by clip 66 to the lay bar 10. Mating connector 68, also retained to the lay bar by clip 66, provides a convenient means to disconnect the binder arm 32 for servicing. Clamp 72 holds the wire 70 in place against the lay bar 10. The wire 70 is retained in connector 68 which is coupled to the housing not shown, wherein the electrical components comprising the circuitry shown in FIG. 4 are mounted. The housing for the circuitry may be mounted in any convenient location on or off the loom.

In the preferred embodiment of the invention the rail 46 functions as the ground reference for the detection system and is the same as the electrical ground used on the loom. If a bracket is used for rail 46, as in the case of a wooden lay bar referred to earlier, a second wire is required. This wire is connected to the bracket, fed through clamp 72 to hold it in place, and then run along side wire 70, as described previously, to the loom ground reference.

In operation, when the shuttle 14 is in flight, contact 54 is in intimate contact with rail 46, which is the loom ground reference, since it is urged in that direction by spring 50 which presses against movable binder arm 32. When the shuttle is boxed (arrives in the shuttle box) the wall 71 of the shuttle l4 exerts a force against movable binder arm 32 sufficient to break the intimate contact between contact 54 and rail 46, thereby removing the ground connection from wires 60 and 70. If the shuttle does not arrive in the shuttle box 12 for any reason, the ground connection would remain on wires 60 and 70. The significance of this will become apparent when the electrical circuitry shown in FIG. 3 is described hereinafter.

The preferred embodiment of the present invention contains two parallel current paths each of which is capable of providing the motor controller with a first voltage, which is referred to as a run voltage and is approximately 0 volts but may be as high as I volt. Only one of the current paths is capable of providing the motor controller with a second voltage, which is referred to as a stop voltage and is approximately 5 volts (B+).

FIG. 3 is a schematic circuit diagram of the preferred embodiment of the present invention wherein the motor controller 74 is shown coupled to a motor 76 which is the source of drive power for the loom not shown. The camshaft 78 of the motor 76 has fixedly mounted thereon cam 80 which activates a switch 82 twice each cycle of the loom. A complete loom cycle being defined as the point wherein the fly-shuttle is returned to its starting point.

A transistor 84 is coupled by resistor 86 to a source of operating voltage of approximately 5 volts (B+) through terminal 88, providing a first current path. The collector electrode of transistor 84 is also coupled to the input terminal of the motor controller 74, theother terminal of the motor controller 74 being coupled to ground reference 90 through terminal 92. The emitter electrode of transistor 84 is coupled to the loom ground reference 90. through terminal 92. A resistor 94 is connected across the base and emitter electrodes of transistor 84. The base electrode of transistor 84 is coupled through the contacts of cam operated switch 82, through a resistor 96, which functions as a relatively constant current source, to a terminal 88 which is connected to a source of operating potential (B+). The B+ voltage, which in the preferred embodiment of the invention is approximately 5 volts, is obtained in a conventional manner from the l2 volt AC winding that is provided on most drive motors or from a separate 12 volt transformer provided to step down the operating line voltage. Although the line voltage may vary at different installations the 12 volts AC is always provided since it is used for other types of protection relays or circuits.

When the contacts of switch 82 are closed resistor 96 supplies sufficient current from B+ to saturate transistor 84 (low voltage drop across the emitter-collector electrodes). With transistor 84 saturated a zero(low) voltage is coupled to the motor controller which in turn permits the motor 76 to run.

A second current path is provided by diode 98 and transistor 100. The collector electrode of transistor 100 is coupled by resistor 102 to B+ terminal 88 and by diode 98 to the input terminal of the motor controller 74. The emitter electrode of transistor 100 is coupled to ground reference 90 through terminal 92. Resistor 104 is connected across the base and emitter electrodes of transistor 100.

A current supplied to the base electrode of transistor 100, will cause it to saturate, thereby causing diode 98 to conduct which provides the motor controller 74 with a zero voltage (actually approximately 1 volt). Transistor 100 is normally unsaturated, (high impedance between the collector and emitter electrodes) and requires an enabling command (current supplied to its base electrode) to saturate and supply the zero voltage to the controller 74. When the transistor 100 is unsaturated, diode 98 prevents any current flow from 8+ and does not effect the voltage at the input terminal of the motor controller. During the time the transistor 100 is unsaturated therefore, the voltage at the input terminal of the motor controller 74 is determined only by the voltage appearing at the collector electrode of transistor 84.

The base electrode of transistor 100 is coupled by a resistor 106 through a first diode 108 to a junction point 110 of resistors 112 and 114, which are serially connected across terminals 88 and 92 (3+ and ground). A switch 116 is connected from the junction point 110 to the terminal 92. The contacts of switch 116 correspond to the rail 46 and the contact 54 shown in FIG. 1, which are part of the shuttle box 12, and function to ground the junction point 110. As long as switch 116 remains closed (shorted) no current can flow into the base electrode of transistor 100.

The base electrode of transistor 100. is coupled in a similar manner by the resistor 106 through a diode 118 to a junction point 120 of resistors 122 and 124, which are serially connected across terminals 88 and 92. A switch 126 is connected from the junction point 120 to terminal 92 and is part of the other shuttle box (not shown) mounted on the left side of the lay bar and functions in the same manner as switch 1 16.

A voltage divider, having a junction point 128 and comprised of resistors 130 and 132, is serially connected from the commonly connected cathode elec trodes of diodes 108 and 118 to terminal 92. The junction point 128 is connected to the base electrode transistor 134. The emitter electrode of transistor 134 is connected to the ground reference 90 via terminal 92. The collector electrode of transistor 134 is coupled via resistor 136 to the source of operating potential via terminal 88.

The collector electrode of transistor 134 is coupled to the base electrode of transistor 138 which has its emitter electrode coupled to ground reference 90 through terminal 92. The collector electrode of transistor 138 is coupled via resistor 140 to the source of operating potential via terminal 88. A capacitor 142 is coupled from the collector electrode of transistor 138 to the ground reference 90 via terminal 92.

A positive voltage appearing at either the junction point 110 or 120 will cause a positive voltage to appear at the base electrode of transistor 134 which will saturate it, thereby causing transistor 138 to turn off (present a high impedance between its emitter and collector electrodes). A high impedance between the collector and emitter electrodes of transistor 138 will allow capacitor 142 to charge to 8+ (5 volts) at a rate determined by the RC time constant of the resistor 140 and the capacitor 142.

When zero volts occurs at both junctions 110 and 120, zero volts appears at the base electrode of transistor 134 causing it to turn off. A high. impedance between the collector and emitter electrodes of transistor 134 permits the resistor 136 to supply sufficient current to the base electrode of transistor 138 to saturate it. With the impedance across the emitter-collector electrodes of transistor 138 being low, capacitor 142 is not permitted to charge.

A silicon unilateral switch (SUS) 144 is coupled from the collector electrode of transistor 138 in series with resistor 146 to the base electrode of transistor 148. The emitter electrode of transistor 148 is connected to the ground reference via terminal 92,

while the collector electrode of transistor 148 is con nected to the base electrode of transistor 100. A resistor 156 is connected from the base electrode to the emitter electrode of transistor 148.

Transistor 148 with no voltage appearing at its base electrode is normally off and has no effect on the performance or functioning of transistor 100. However, when capacitor 142 reaches the breakover voltage of the SUS 144, capacitor 142 will discharge into the base electrode of transistor 148 causing transistor 148 to saturate. A low impedance between the collector and emitter electrodes of transistor 148 shunts the base electrode current of transistor and turns off transistor 100, thus removing the zero or run signal voltage from the motor controller 74. The discharge time constant of capacitor 142 is much longer than the charging time constant since the discharge time constant is determined by resistor 146 and capacitor 142 while the charging time constant is determined by resistor and capacitor 142. The discharge time of capacitor 142 is effectively increased by the action of the SUS 144 since it remains conductive (on) once its breakover voltage has been reached thereby supplying current to the base electrode of transistor 148 from B+ via resistors 140 and 146. The discharge time is sufficiently long to hold transistor 100 open until cam 80 opens switch 82 which turns transistor 84 off thereby effecting a stop signal voltage for the motor controller 74.

In operation the circuit shown in FIG. 3 functions normally in accordance with the curves shown'in FIGS.

4 A, 48 and 4C. The curves of FIGS. 4A, 4B, and 4C are voltage timing diagrams showing the voltages at various points in the schematic circuit diagram of FIG. 3 at different times in the loom cycle, with the voltage amplitude indicated on the vertical axis and the time indicated on the horizontal axis.

The curve 150 of FIG. 43 represents the zero (low voltage) run signal voltage that is required to be coupled to the motor controller 74 for the motor controller to enable the motor 76 to continue driving the loom for the complete loom cycle. The curve 152 of FIG. 4A represents the voltage appearing at the collector electrode of transistor 84 (FIG. 3) with respect to terminal 92 which is connected to the loom ground reference 90. The voltage at the collector of transistor 84 varies from zero volts (in actualpractiice approximately 1 volt) to a value of approximately 5 volts (3+). The change from a level of 0 volts occurs twice each loom cycle 154 (FIG. 4C), responsive to the action of cam 80 mounted on the cam shaft 78 (FIG. 3).

The cam 80 is selected to provide the 5 volt (stop) signal during a portion of the time thatthe fly-shuttle 14 is normally boxed. If the stop signal voltage (5 volts) is not reduced to zero volts by a second parallel current path the motor controller will stop the motor. However, a second parallel path is supplied by diode 98 and transistor 100 (FIG. 3). The voltage appearing from the collector of transistor 100 to terminal 92 is shown as curve 158 of FIG. 4C.

With the fly-shuttle 14 in flight, switches 116 and 126 (FIG. 3) are closed and the voltage at the collector electrode of transistor 100 is approximately 5 volts (B+) (curve portion 160, FIG. 4C). Because of the blocking action of the now reverse biased diode 98, no signal voltage is applied to the motor controller via transistor 100. This allows the cam 80 (FIG. 3) associated with transistor 84 to determine when the motor will run. The cam 80 permits switch 82 to remain closed during the time that the fly-shuttle 14 is in flight. This permits resistor 96 to supply sufficient current from B+ to saturate transistor 84 (curve portion 162 FIG. 4A and provide the zero signal voltage to the motor controller 74 which allows the motor 76 to run.

Cam 80 opens switch 82 at the time in the loom cycle that fly-shuttle 14 is normally boxed. During this time the voltage at the collector electrode of transistor 84 (curve portion 154 FIG. 4A) jumps to 8+ since the base electrode current is no longer supplied by resistor 96. If the shuttle 14 is not boxed during this time interval or if switches 116 or 126 are shorted the motor controller 74 will stop the motor 76.

However, if fly-shuttle 14 has arrived in a shuttle box during this normal time interval then either switch 116 or switch 126 will be opened by the shuttle and a positive voltage will appear at junction point 110 or 120. A positive voltage will be coupled to the base electrode of transistor 100 causing it to saturate thereby permitting diode 98 to conduct current toward the ground reference 90 via terminal 92, providing the zero or run signal voltage for the motor controller. The total voltage drop across the diode and emitter-collector electrode of transistor 190 being approximately equal to 1 volt.

Thus, the opening of switch 116 or 126 provides the enabling voltage for transistor 100 to provide the run signal voltage.

However, a positive voltage applied to either junction point 110 or junction point 120 starts the charging of capacitor 142, as explained earlier, and after a predetermined delay the SUS 144 fires (point 164 of FIG. 4C) saturating transistor 148. A low impedance between the collector and emitter electrodes of transistor 148 shunts the base electrode current from transistor 100 turning it off, thus causing the collector electrode to become B+ again (curve portion 160 FIG. 4C).

If switches 116 or 126 were to fail in the open condition then junction 110 or 120 would have a continuous DC voltage thereon. A continuous positive voltage would then be applied to the base electrode of transistor 100 causing it to become saturated. This cou pled a run signal voltage to the motor controller. In a relatively short time the capacitor 142 is charged to the breakover voltage of the SUS 144, causing the capacitor 142 to discharge into the base electrode of transistor 140. Additional base electrode current is supplied through resistors 140 and 146 from B+. Transistor 148 saturates and thus turns off transistor 100. Once the SUS 144 has fired it stays on, thereby holding transistor 100 open until cam 80 opens switch 82 interrupting the base electrode current drive for transistor 84 turning it off. Since neither transistor 84 nor transistor 100 is providing a zero signal voltage to the motor controller 74 during this time interval the motor 76 stops.

Under normal operation, each time the shuttle 14 is in flight switches 116 and 126 are permitted to close.

This turns off transistor 134 saturating transistor 138 and discharging capacitor 142 to zero volts, thereby resetting the SUS 144 to its unfired state. Therefore, the timing interval for capacitor 142 and resistor starts from zero each time the shuttle 14 is boxed.

It is also to be noted that increased reliability of the electronic circuitry itself can be improved by including redundant circuits according to standard conventional techniques. However, the present system is relatively fail-safe when compared to present state of the art systems since the most frequent component to fail is the shuttle sensing switches and in the present system both switch failure modes provide for stopping the drive motor.

Heretofore has been disclosed a shuttle boxing detector which provides a fast, reliable essentially failsafe manner of detecting when a fly-shuttle has properly entered a shuttle box. The present system will also stop the drive motor if the fly-shuttle has bounced out of the shuttle box shortly after arriving therein. Present shuttle box binder arms may be readily modified for use with the preferred embodiment of the present invention at a low cost.

Having thus set forth the nature of the invention what we claim herein is:

1. In a weaving loom having a fly-shuttle, an electric motor drive means responsive to a motor controller, a lay bar with shuttle boxes at both ends, a shuttle boxing detector comprising:

a. a first and second switch means fixedly disposed respectively on said shuttle boxes for providing an enabling voltage upon the boxing of said fly-shuttle, each said switch means including first and second resistors connected in series across a first terminal adapted to be connected to a source of operating potential and a second terminal adapted to be connected to a ground reference, said first and second resistors having a common junction point, a switch having a pair of normally closed contacts connected from said common junction point to said second terminal, said switch contacts being opened upon boxing of said fly-shuttle, and a first diode coupled from said junction point to a third terminal, the voltage from said third terminal to ground being substantially zero when said flyshuttle is in flight and equal to a portion of said operating potential when said fly-shuttle is boxed;

. first means coupled between said first and second switch means and said motor controller for providing a first voltage to said motor controller, said first means including a first transistor having collector, base, and emitter electrodes, said collector electrode being resistively coupled to said first terminal, said base electrode being resistively coupled to the third terminal of said first and second switch means, and said emitter electrode being coupled to said second terminal, and a second diode coupled from said collector electrode to said motor controller;

. second means coupled to said first and second switch means and said first means for removing said first voltage a predetermined time interval after said fly-shuttle has been boxed in either of said shuttle boxes, said second means including a DC amplifying means having an input and an output terminal, said inputterminal being coupled to the third terminal of said first and second switch means for providing a DC voltage at said output terminal when said enabling voltage appears at said input terminal, a capacitor coupled between said output terminal and said second terminal, and third switch means coupled between said output terminal and the base electrode of said first transistor, for causing said first means to remove said first voltage when said capacitor charges to a predetermined threshold value; and

d. third means coupled to said motor controller for providing said first voltage and a second voltage responsive to the position of the lay bar in the loom cycle, said second voltage being provided only during a portion of the time said fly-shuttle is normally boxed, whereby said motor drive means is stopped unless said motor controller is provided with said first voltage, said third means including, a second transistor having emitter, base, and collector electrodes, said collector electrode being resistively coupled to said first terminaland coupled to said motor controller, said emitter electrode being coupled to said second terminal, a relatively constant current source, and a cam operated switch coupled between said constant current source and the base electrode of said second transistor, said cam being fixedly mounted on the crankshaft of said loom for opening said cam operated switch and interrupting the flow of current from said relatively constant current source to wherein said DC amplifying means comprises:

a. a voltage divider means having a junction point,

said voltage divider means being coupled across said DC amplifying input terminal and said second terminal for providing a portion of said enabling voltage at said junction point;

b. a third transistor having emitter, base, and collector electrodes, said emitter electrode being coupled to said second terminal, said base electrode being coupled to said voltage divider junction point, said collector electrode being resistively coupled to said first terminal; and

c. afourth transistor having emitter, base, and collector electrodes, said emitter electrode being coupled to said second terminal, said base electrode being coupled to the collector electrode of said third transistor, said collector electrode being resistively coupled to said first terminal.

3. A shuttle boxing detector according to claim 1 wherein said third switch means comprises:

the base electrode of said second transistor at a. a fifth transistor having emitter, base, and collector electrodes, said emitter electrode being coupled to said second terminal, said collector electrode being coupled to the base electrode of said first transistor, said base electrode being resistively coupled to said second terminal; and

b. a silicon unilateral switch (SUS) coupled to said DC amplifying means output terminal and resistively coupled to the base electrode of said fifth transistor. 4. A shuttle boxing detector according to claim 1 wherein said relatively constant current source comprises a resistor coupled from said first terminal to said cam operated switch means. 

1. In a weaving loom having a fly-shuttle, an electric motor drive means responsive to a motor controller, a lay bar with shuttle boxes at both ends, a shuttle boxing detector comprising: a. a first and second switch means fixedly disposed respectively on said shuttle boxes for providing an enabling voltage upon the boxing of said fly-shuttle, each said switch means including first and second resistors connected in series across a first terminal adapted to be connected to a source of operating potential and a second terminal adapted to be connected to a ground reference, said first and second resistors having a common junction point, a switch having a pair of normally closed contacts connected from said common junction point to said second terminal, said switch contacts being opened upon boxing of said fly-shuttle, and a first diode coupled from said junction point to a third terminal, the voltage from said third terminal to ground being substantially zero when said fly-shuttle is in flight and equal to a portion of said operating potential when said fly-shuttle is boxed; b. first means coupled between said first and second switch means and said motor controller for providing a first voltage to said motor controller, said first means including a first transistor having collector, base, and emitter electrodes, said collector electrode being resistively coupled to said first terminal, said base electrode being resistively coupled to the third terminal of said first and second switch means, and said emitter electrode being coupled to said second terminal, and a second diode coupled from said collector electrode to said motor controller; c. second means coupled to said first and second switch means and said first means for removing said first voltage a predetermined time interval after said fly-shuttle has been boxed in either of said shuttle boxes, said second means including a DC amplifying means having an input and an output terminal, said input terminal being coupled to the third terminal of said first and second switch means for providing a DC voltage at said output terminal when said enabling vOltage appears at said input terminal, a capacitor coupled between said output terminal and said second terminal, and third switch means coupled between said output terminal and the base electrode of said first transistor, for causing said first means to remove said first voltage when said capacitor charges to a predetermined threshold value; and d. third means coupled to said motor controller for providing said first voltage and a second voltage responsive to the position of the lay bar in the loom cycle, said second voltage being provided only during a portion of the time said flyshuttle is normally boxed, whereby said motor drive means is stopped unless said motor controller is provided with said first voltage, said third means including, a second transistor having emitter, base, and collector electrodes, said collector electrode being resistively coupled to said first terminal and coupled to said motor controller, said emitter electrode being coupled to said second terminal, a relatively constant current source, and a cam operated switch coupled between said constant current source and the base electrode of said second transistor, said cam being fixedly mounted on the crankshaft of said loom for opening said cam operated switch and interrupting the flow of current from said relatively constant current source to the base electrode of said second transistor at prescribed intervals of the loom cycle.
 1. In a weaving loom having a fly-shuttle, an electric motor drive means responsive to a motor controller, a lay bar with shuttle boxes at both ends, a shuttle boxing detector comprising: a. a first and second switch means fixedly disposed respectively on said shuttle boxes for providing an enabling voltage upon the boxing of said fly-shuttle, each said switch means including first and second resistors connected in series across a first terminal adapted to be connected to a source of operating potential and a second terminal adapted to be connected to a ground reference, said first and second resistors having a common junction point, a switch having a pair of normally closed contacts connected from said common junction point to said second terminal, said switch contacts being opened upon boxing of said fly-shuttle, and a first diode coupled from said junction point to a third terminal, the voltage from said third terminal to ground being substantially zero when said fly-shuttle is in flight and equal to a portion of said operating potential when said fly-shuttle is boxed; b. first means coupled between said first and second switch means and said motor controller for providing a first voltage to said motor controller, said first means including a first transistor having collector, base, and emitter electrodes, said collector electrode being resistively coupled to said first terminal, said base electrode being resistively coupled to the third terminal of said first and second switch means, and said emitter electrode being coupled to said second terminal, and a second diode coupled from said collector electrode to said motor controller; c. second means coupled to said first and second switch means and said first means for removing said first voltage a predetermined time interval after said fly-shuttle has been boxed in either of said shuttle boxes, said second means including a DC amplifying means having an input and an output terminal, said input terminal being coupled to the third terminal of said first and second switch means for providing a DC voltage at said output terminal when said enabling vOltage appears at said input terminal, a capacitor coupled between said output terminal and said second terminal, and third switch means coupled between said output terminal and the base electrode of said first transistor, for causing said first means to remove said first voltage when said capacitor charges to a predetermined threshold value; and d. third means coupled to said motor controller for providing said first voltage and a second voltage responsive to the position of the lay bar in the loom cycle, said second voltage being provided only during a portion of the time said fly-shuttle is normally boxed, whereby said motor drive means is stopped unless said motor controller is provided with said first voltage, said third means including, a second transistor having emitter, base, and collector electrodes, said collector electrode being resistively coupled to said first terminal and coupled to said motor controller, said emitter electrode being coupled to said second terminal, a relatively constant current source, and a cam operated switch coupled between said constant current source and the base electrode of said second transistor, said cam being fixedly mounted on the crankshaft of said loom for opening said cam operated switch and interrupting the flow of current from said relatively constant current source to the base electrode of said second transistor at prescribed intervals of the loom cycle.
 2. A shuttle boxing detector according to claim 1 wherein said DC amplifying means comprises: a. a voltage divider means having a junction point, said voltage divider means being coupled across said DC amplifying input terminal and said second terminal for providing a portion of said enabling voltage at said junction point; b. a third transistor having emitter, base, and collector electrodes, said emitter electrode being coupled to said second terminal, said base electrode being coupled to said voltage divider junction point, said collector electrode being resistively coupled to said first terminal; and c. a fourth transistor having emitter, base, and collector electrodes, said emitter electrode being coupled to said second terminal, said base electrode being coupled to the collector electrode of said third transistor, said collector electrode being resistively coupled to said first terminal.
 3. A shuttle boxing detector according to claim 1 wherein said third switch means comprises: a. a fifth transistor having emitter, base, and collector electrodes, said emitter electrode being coupled to said second terminal, said collector electrode being coupled to the base electrode of said first transistor, said base electrode being resistively coupled to said second terminal; and b. a silicon unilateral switch (SUS) coupled to said DC amplifying means output terminal and resistively coupled to the base electrode of said fifth transistor. 